Question

Which of the following statements are correct in relation to the rotational characteristics of planets in our solar system?

1. With the exception of Venus and Mars, all the planets rotate in the same clockwise direction
2. With the exception of Uranus and Neptune, all the planets rotate in the same counter clockwise direction
3. With the exception of Venus and Uranus, all the planets rotate in the same counter clockwise direction
4. All the planets orbits lie close to the same plane (the plane of the ecliptic) passing through the Sun's equator

• A. ii only
• B. iii, iv
• C. i, iii
• D. iii only

Answer 1

Answer:

B. iii, iv

Planetary Rotation Characteristics

• Most planets in our solar system exhibit prograde rotation, meaning they rotate counter-clockwise when viewed from above their North Pole.
• There are two main exceptions to this general rule:
• Venus: This planet has a retrograde rotation, meaning it rotates clockwise. Its rotation is extremely slow, taking longer to complete one rotation than it does to orbit the Sun.
• Uranus: This gas giant rotates on its side, with an axial tilt of approximately 98 degrees. This extreme tilt makes its rotation appear retrograde from a conventional perspective.
• Planets like Mars and Neptune, despite being mentioned in incorrect options, rotate in the standard counter-clockwise (prograde) direction.

Planetary Orbital Planes

• All the planets in our solar system orbit the Sun in a relatively flat plane, known as the plane of the ecliptic.
• The ecliptic plane is essentially the plane of Earth's orbit around the Sun.
• This co-planar arrangement is a direct result of the solar system's formation from a rotating protoplanetary disk of gas and dust, which flattened out over time.
• While planets' orbits are very close to the ecliptic, there are slight inclinations (deviations) for each planet. However, they are all generally within a few degrees of this plane.
• For competitive exams, it's worth noting that Pluto (now classified as a dwarf planet) has a significantly inclined orbit (about 17 degrees) compared to the main planets, and it also has a highly elliptical orbit.